U.S. Pat. No. 5,040,833 to Brunnert discloses a “closing device for a drawer” and includes a drawer installed to a piece of furniture and the drawer is movable between a closed position and an opened position on the piece of furniture. A spring is located between the drawer and the piece of the furniture. A closing device is connected to the piece of the furniture and includes a holding member which has a hook-shaped end. A latch member is connected to the drawer. When the drawer is located at the closed position, the latch member is engaged with the hook-shaped end of the holding member. The latch member has at least one raised area which has at least two guide tracks for guiding the holding member. When the drawer is movable between the closed and opened positions, the holding member is guided by the two different guide tracks and bent. When the drawer is pulled out from the piece of the furniture improperly, the upward deformation of the holding member makes the hook-shaped end be disengaged from the latch member. When a force pushes the drawer which is at its closed position, the hook-shaped end of the holding member is movable and disengaged from the latch member, so that the drawer pops out from the piece of the furniture in response to the force of the spring.
U.S. Pat. No. 7,374,261 to Wang discloses a “push-open type slide structure” and includes a top fastener and a locking device between an outer slide rail and a pull rod. The loading plate is extended from one side of the center portion of the main body. Two pillars are extended from both sides of the main body. A positioning fastener is coupled with the loading plate. A hook is mounted on the inner edge of the loading plate. A guide pillar is mounted on the rear end of the loading plate. The hook is inserted into the action trench of the main body and coupled with the elastic device. The locking device has a connection part for coupling with a guide part and a shaft holder. The push-open type slide structure is lockable or unlockable by pivotal rotation between the loading plate and the locking device.
Besides, a protection device is disclosed by Brunnert and Wang so as to protect the parts when the drawer is forcibly pulled out. Brunnert uses the holding member which is deformed upward so that the hook is disengaged from the latch member. Wang discloses a slot defined in the loading plate and the slot is located corresponding to the underside of the pillar such that the end with the pillar of the positioning fastener can be deformed so that the pillar can be removed from the locking device. However, both of the two protections are functioned by the deformation of the related parts to release the engagement. Nevertheless, the contact portions between two parts tend to be worn out after several times of operation so that the life of use is shortened. Besides, in order to allow the deformed part to bounce back, the portion that is deformed cannot be too stiff, accordingly, the response force to bear the force pulling the drawer out from the rails is weak. The structure cannot be used for a large drawer or heavy duty slide assembly because the drawer could open unexpectedly.
The present invention intends to provide an opening mechanism for a slide assembly and the opening mechanism improves the shortcomings of the conventional structures mentioned above.